#include <iostream>
#include <string>
#include <functional>
using namespace std;




//函数对象
//using Task = function<void()>;

//类
class Task
{
public:
    Task(){}
    Task(int a,int b):_a(a),_b(b),_result(0)
    {}
    void Excute()
    {
        _result = _a + _b;
    }
    string Add()
    {
        string s =  "_a + _b = ?";
        return s;
    }
    string Result()
    {
        string s =  to_string(_a) + " + " + to_string(_b) + " = " + to_string(_result);
        return s;
    }

    void operator()()
    {
        Excute();
    }
    
    ~Task()
    {}

private:
    int _a;
    int _b;
    int _result;
};